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ELife Oct 2023Activation of the Wnt pathway lies at the core of many human cancers. Wnt and macropinocytosis are often active in the same processes, and understanding how Wnt...
Activation of the Wnt pathway lies at the core of many human cancers. Wnt and macropinocytosis are often active in the same processes, and understanding how Wnt signaling and membrane trafficking cooperate should improve our understanding of embryonic development and cancer. Here, we show that a macropinocytosis activator, the tumor promoter phorbol 12-myristate 13-acetate (PMA), enhances Wnt signaling. Experiments using the embryo as an in vivo model showed marked cooperation between the PMA phorbol ester and Wnt signaling, which was blocked by inhibitors of macropinocytosis, Rac1 activity, and lysosome acidification. Human colorectal cancer tissue arrays and xenografts in mice showed a correlation of cancer progression with increased macropinocytosis/multivesicular body/lysosome markers and decreased GSK3 levels. The crosstalk between canonical Wnt, focal adhesions, lysosomes, and macropinocytosis suggests possible therapeutic targets for cancer progression in Wnt-driven cancers.
Topics: Female; Pregnancy; Humans; Animals; Mice; Carcinogens; Wnt Signaling Pathway; Glycogen Synthase Kinase 3; Phorbol Esters; Esters; Neoplasms
PubMed: 37902809
DOI: 10.7554/eLife.89141 -
Biomedicine & Pharmacotherapy =... Jul 2023Research on transient receptor potential vanilloid-4 (TRPV4) can provide a promising potential therapeutic target in the development of novel medicines for lung... (Review)
Review
Research on transient receptor potential vanilloid-4 (TRPV4) can provide a promising potential therapeutic target in the development of novel medicines for lung disorders. TRPV4 expresses in lung tissue and plays an important role in the maintenance of respiratory homeostatic function. TRPV4 is upregulated in life-threatening respiratory diseases like pulmonary hypertension, asthma, cystic fibrosis, and chronic obstructive pulmonary diseases. TRPV4 is linked to several proteins that have physiological functions and are sensitive to a wide variety of stimuli, such as mechanical stimulation, changes in temperature, and hypotonicity, and responds to a variety of proteins and lipid mediators, including anandamide (AA), the arachidonic acid metabolite, 5,6-epoxyeicosatrienoic acid (5,6-EET), a plant dimeric diterpenoid called bisandrographolide A (BAA), and the phorbol ester 4-alpha-phorbol-12,13-didecanoate (4α-PDD). This study focused on relevant research evidence of TRPV4 in lung disorders and its agonist and antagonist effects. TRPV4 can be a possible target of discovered molecules that exerts high therapeutic potential in the treatment of respiratory diseases by inhibiting TRPV4.
Topics: Humans; Transient Receptor Potential Channels; TRPV Cation Channels; Phorbol Esters; Hypertension, Pulmonary
PubMed: 37178575
DOI: 10.1016/j.biopha.2023.114861 -
Theranostics 2020Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease characterized by autoantibody production by hyper-activated B cells. Although mesenchymal stem...
Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease characterized by autoantibody production by hyper-activated B cells. Although mesenchymal stem cells (MSCs) ameliorate lupus symptoms by inhibiting T cells, whether they inhibit B cells has been controversial. Here we address this issue and reveal how to prime MSCs to inhibit B cells and improve the efficacy of MSCs in SLE. We examined the effect of MSCs on purified B cells and the therapeutic efficacy of MSCs in lupus-prone MRL. mice. We screened chemicals for their ability to activate MSCs to inhibit B cells. Mouse bone marrow-derived MSCs inhibited mouse B cells in a CXCL12-dependent manner, whereas human bone marrow-derived MSCs (hMSCs) did not inhibit human B (hB) cells. We used a chemical approach to overcome this hurdle and found that phorbol myristate acetate (PMA), phorbol 12,13-dibutyrate, and ingenol-3-angelate rendered hMSCs capable of inhibiting IgM production by hB cells. As to the mechanism, PMA-primed hMSCs attracted hB cells in a CXCL10-dependent manner and induced hB cell apoptosis in a PD-L1-dependent manner. Finally, we showed that PMA-primed hMSCs were better than naïve hMSCs at ameliorating SLE progression in MRL. mice. Taken together, our data demonstrate that phorbol esters might be good tool compounds to activate MSCs to inhibit B cells and suggest that our chemical approach might allow for improvements in the therapeutic efficacy of hMSCs in SLE.
Topics: Animals; Apoptosis; B-Lymphocytes; Cells, Cultured; Female; Humans; Lupus Erythematosus, Systemic; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Mice, Inbred C3H; Phorbol Esters; T-Lymphocytes
PubMed: 32929342
DOI: 10.7150/thno.46835 -
International Journal of Molecular... Nov 2012The physic nut shrub, Jatropha curcas (Euphorbiaceae), has been considered as a "miracle tree", particularly as a source of alternate fuel. Various extracts of the plant... (Review)
Review
The physic nut shrub, Jatropha curcas (Euphorbiaceae), has been considered as a "miracle tree", particularly as a source of alternate fuel. Various extracts of the plant have been reported to have insecticidal/acaricidal or molluscicidal/anthelminthic activities on vectors of medical or veterinary interest or on agricultural or non-agricultural pests. Among those extracts, the phorbol ester fraction from seed oil has been reported as a promising candidate for use as a plant-derived protectant of a variety of crops, from a range of pre-harvest and post-harvest insect pests. However, such extracts have not been widely used, despite the "boom" in the development of the crop in the tropics during recent years, and societal concerns about overuse of systemic chemical pesticides. There are many potential explanations to such a lack of use of Jatropha insecticidal extracts. On the one hand, the application of extracts potentially harmful to human health on stored food grain, might not be relevant. The problem of decomposition of phorbol esters and other compounds toxic to crop pests in the field needing further evaluation before such extracts can be widely used, may also be a partial explanation. High variability of phorbol ester content and hence of insecticidal activity among physic nut cultivars/ecotypes may be another. Phytotoxicity to crops may be further limitation. Apparent obstacles to a wider application of such extracts are the costs and problems involved with registration and legal approval. On the other hand, more studies should be conducted on molluscicidal activity on slugs and land snails which are major pests of crops, particularly in conservation agriculture systems. Further evaluation of toxicity to natural enemies of insect pests and studies on other beneficial insects such as pollinators are also needed.
Topics: Animals; Chemical Fractionation; Crops, Agricultural; Humans; Insect Control; Insecticides; Jatropha; Phorbol Esters; Plant Extracts; Plant Oils; Seeds
PubMed: 23203190
DOI: 10.3390/ijms131216157 -
British Journal of Pharmacology Apr 2003This review focuses on the effects of phorbol esters and the role of phorbol ester receptors in the secretion of neurotransmitter substances. We begin with a brief... (Review)
Review
This review focuses on the effects of phorbol esters and the role of phorbol ester receptors in the secretion of neurotransmitter substances. We begin with a brief background on the historical use of phorbol esters as tools to decipher the role of the enzyme protein kinase C in signal transduction cascades. Next, we illustrate the structural differences between active and inactive phorbol esters and the mechanism by which the binding of phorbol to its recognition sites (C1 domains) on a particular protein acts to translocate that protein to the membrane. We then discuss the evidence that the most important nerve terminal receptor for phorbol esters (and their endogenous counterpart diacylglycerol) is likely to be Munc13. Indeed, Munc13 and its invertebrate homologues are the main players in priming the secretory apparatus for its critical function in the exocytosis process.
Topics: Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Carrier Proteins; Drosophila; Models, Biological; Neurotransmitter Agents; Phorbol Esters; Protein Kinase C; Receptors, Drug
PubMed: 12711617
DOI: 10.1038/sj.bjp.0705213 -
The Journal of Biological Chemistry Jul 1986A mixed micellar assay for the binding of phorbol-esters to protein kinase C was developed to investigate the specificity and stoichiometry of phospholipid cofactor...
A mixed micellar assay for the binding of phorbol-esters to protein kinase C was developed to investigate the specificity and stoichiometry of phospholipid cofactor dependence and oligomeric state of protein kinase C (Ca2+/phospholipid-dependent enzyme) required for phorbol ester binding. [3H]Phorbol dibutyrate was bound to protein kinase C in the presence of Triton X-100 mixed micelles containing 20 mol % phosphatidylserine (PS) in a calcium-dependent manner with a Kd of 5 X 10(-9) M. The [3H]phorbol dibutyrate X protein kinase C . Triton X-100 . PS mixed micellar complex eluted on a Sephacryl S-200 molecular sieve at an Mr of approximately 200,000; this demonstrates that monomeric protein kinase C binds phorbol dibutyrate. This conclusion was supported by molecular sieve chromatography of a similar complex where Triton X-100 was replaced with beta-octylglucoside. Phorbol dibutyrate activation of protein kinase C in Triton X-100/PS mixed micelles occurred and was dependent on calcium. The PS dependence of both phorbol ester activation and binding to protein kinase C lagged initially and then was highly cooperative. The minimal mole per cent PS required was strongly dependent on the concentration of phorbol dibutyrate or phorbol myristic acetate employed. Even at the highest concentration of phorbol ester tested, a minimum of 3 mol % PS was required; this indicates that approximately four molecules of PS are required. [3H]Phorbol dibutyrate binding was independent of micelle number at 20 mol % PS. The phospholipid dependencies of phorbol ester binding and activation were similar, with PS being the most effective; anionic phospholipids (cardiolipin, phosphatidic acid, and phosphatidylglycerol were less effective, whereas phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin did not support binding or activation. sn-1,2-Dioleoylglycerol displaced [3H]phorbol dibutyrate quantitatively and competitively. The data are discussed in relation to a molecular model of protein kinase C activation.
Topics: Animals; Calcium; Chromatography, Gel; Colloids; Enzyme Activation; Female; Macromolecular Substances; Micelles; Octoxynol; Phorbol 12,13-Dibutyrate; Phorbol Esters; Phosphatidylserines; Phospholipids; Polyethylene Glycols; Protein Kinase C; Rats
PubMed: 3459728
DOI: No ID Found -
Molecular Carcinogenesis Jun 2017Few kinases have been studied as extensively as protein kinase C (PKC), particularly in the context of cancer. As major cellular targets for the phorbol ester tumor... (Review)
Review
Few kinases have been studied as extensively as protein kinase C (PKC), particularly in the context of cancer. As major cellular targets for the phorbol ester tumor promoters and diacylglycerol (DAG), a second messenger generated by stimulation of membrane receptors, PKC isozymes play major roles in the control of signaling pathways associated with proliferation, migration, invasion, tumorigenesis, and metastasis. However, despite decades of research, fundamental questions remain to be answered or are the subject of intense controversy. Primary among these unresolved issues are the role of PKC isozymes as either tumor promoter or tumor suppressor kinases and the incomplete understanding on isozyme-specific substrates and effectors. The involvement of PKC isozymes in cancer progression needs to be reassessed in the context of specific oncogenic and tumor suppressing alterations. In addition, there are still major hurdles in addressing isozyme-specific function due to the limited specificity of most pharmacological PKC modulators and the lack of validated predictive biomarkers for response, which impacts the translation of these agents to the clinic. In this review we focus on key controversial issues and upcoming challenges, with the expectation that understanding the intricacies of PKC function will help fulfill the yet unsuccessful promise of targeting PKCs for cancer therapeutics.
Topics: Animals; Antineoplastic Agents; Diglycerides; Disease Progression; Humans; Isoenzymes; Molecular Targeted Therapy; Neoplasms; Phorbol Esters; Protein Kinase C; Substrate Specificity
PubMed: 28112438
DOI: 10.1002/mc.22617 -
The Journal of Biological Chemistry Sep 2002Diacylglycerol kinase (DGK) plays an important role in signal transduction through modulating the balance between two signaling lipids, diacylglycerol and phosphatidic...
Diacylglycerol kinase (DGK) plays an important role in signal transduction through modulating the balance between two signaling lipids, diacylglycerol and phosphatidic acid. In yeast two-hybrid screening, we unexpectedly found a self-association of the C-terminal part of DGKdelta containing a sterile alpha-motif (SAM) domain. We then bacterially expressed the SAM domain fused with maltose-binding protein and confirmed the formation of dimeric and tetrameric structures. Moreover, gel filtration and co-immunoprecipitation analyses demonstrated that DGKdelta formed homo-oligomeric structures in intact cells and that the SAM domain was critically involved in the oligomerization. Interestingly, phorbol ester stimulation induced dissociation of the oligomeric structures with concomitant phosphorylation of DGKdelta. Furthermore, we found that DGKdelta was translocated from cytoplasmic vesicles to the plasma membrane upon phorbol ester stimulation. In this case, DGKdelta mutants lacking the ability of self-association were localized at the plasma membranes even in the absence of phorbol ester. A protein kinase C inhibitor, staurosporine, blocked all of the effects of phorbol ester, i.e. oligomer dissociation, phosphorylation, and translocation. We confirmed that tumor-promoting phorbol esters did not directly bind to DGKdelta. The present studies demonstrated that the formation and dissociation of oligomers serve as the regulatory mechanisms of DGKdelta and that DGKdelta is a novel downstream effector of phorbol ester/protein kinase C signaling pathway.
Topics: Animals; Biopolymers; Blotting, Western; COS Cells; Chromatography, Gel; Diacylglycerol Kinase; Enzyme Activation; Phosphorylation; Precipitin Tests; Protein Transport; Subcellular Fractions; Tetradecanoylphorbol Acetate; Two-Hybrid System Techniques
PubMed: 12084710
DOI: 10.1074/jbc.M202035200 -
Journal of Neurochemistry Mar 2008GN11 and GT1-7 are immortalized gonadotropin-releasing hormone-positive murine cell lines exhibiting the features of immature olfactory neurons and differentiated...
GN11 and GT1-7 are immortalized gonadotropin-releasing hormone-positive murine cell lines exhibiting the features of immature olfactory neurons and differentiated hypothalamic neurons, respectively. Using electron microscopy and biochemical assays (RT-PCR and immunoblotting) we determined the presence of numerous caveolae invaginations and of caveolin-1 and -2 mRNAs and proteins in GN11 cells, and their absence in GT1-7 cells. The lack of caveolins in GT1-7 cells might be due to the silencing of gene transcription caused by estrogen receptor alpha whose inhibitory activity in GN11 cells could be counter-balanced by co-expression of caveolin-permissive estrogen receptor beta. To test whether the unique expression of caveolins in GN11 cells is related to their immature state, we treated GN11 cells for 24-72 h with retinoic acid or phorbol ester. Both treatments led to neuronal differentiation of GN11 cells, as shown by emission of long neuritic processes, increased expression of growth cone-associated protein-43 and appearance of voltage-gated K+ and C2+ channel currents. Concurrently, caveolins 1 and 2, and estrogen receptor beta were down-regulated in differentiated GN11, whereas estrogen receptor alpha was unaffected by differentiation. We conclude that caveolin expression in GN11 neurons is down-regulated upon differentiation and up-regulated by estrogen receptor beta.
Topics: Animals; Antineoplastic Agents; Brain Neoplasms; Calcium Channels; Caveolin 1; Caveolin 2; Cell Differentiation; Cell Line, Tumor; Down-Regulation; Estrogen Receptor alpha; Estrogen Receptor beta; Gene Expression; Gonadotropin-Releasing Hormone; Membrane Potentials; Mice; Neurons; Patch-Clamp Techniques; Phorbol Esters; Tretinoin
PubMed: 17988240
DOI: 10.1111/j.1471-4159.2007.05109.x -
IUBMB Life Jun 2019Protein kinase C (PKC) is activated by 1,2-diacylglycerol as a second messenger in the signaling mechanism coupled with the hydrolysis of membrane inositol... (Review)
Review
Protein kinase C (PKC) is activated by 1,2-diacylglycerol as a second messenger in the signaling mechanism coupled with the hydrolysis of membrane inositol phospholipids, although it was not found by screening for a 1,2-diacylglycerol-dependent enzyme. PKC is also a receptor for the tumor-promoting phorbol esters, but it was not identified by its property of binding phorbol esters, either. Instead, the discovery and characterization of PKC, now known to comprise a family with multiple isoforms, was through a circuitous voyage filled with unexpected twists and turns. This review summarizes the discovery and the initial experiments of PKC as a historical perspective of the enzyme family in the context of the progress in the studies on protein phosphorylation. © 2018 IUBMB Life, 71(6):697-705, 2019.
Topics: Diglycerides; Humans; Hydrolysis; Phorbol Esters; Phosphatidylinositols; Phosphorylation; Protein Binding; Protein Kinase C; Proteins
PubMed: 30393952
DOI: 10.1002/iub.1963